(294 days)
The NOVOS-NAIL Limb Lengthening System is indicated for limb lengthening of the femur and tibia.
The Smith & Nephew NOVOS-NAIL Limb Lengthening System (NOVOS-NAIL LLS) is composed of a modular implantable intramedullary rod, locking screws, and an external actuator. The modular implantable rod is available in different configurations, lengths, and diameters to accommodate a variety of patient anatomies. The system uses locking screws and nail caps (optional) previously cleared with the TRIGEN Nail system (K981529).
The NOVOS-NAIL implant includes an enclosed rare earth magnet, telescoping lead screw/nut assembly and gearing. The subject device is supplied sterile by gamma sterilization. The external actuator is supplied non sterile.
This is a set of acceptance criteria for a medical device called the NOVOS-NAIL Limb Lengthening System (LLS). The acceptance criteria and supporting studies are presented below:
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criteria | Reported Device Performance | Study that Proves the Device Meets the Acceptance Criteria |
|---|---|---|
| Structural Strength | Evaluated for retrograde femoral and antegrade tibia loading configurations | Finite Element Analysis (FEA) of 8mm and 11mm NOVOS Limb Lengthening Nails |
| Construct Fatigue Performance | Equivalent to the predicate device | Construct Fatigue Testing on 8mm and 11mm NOVOS-NAIL and predicate device |
| Bending Fatigue Performance | Similar to the predicate device, identified potential failure modes | Bending Fatigue Evaluation of 8mm and 11mm NOVOS-NAIL |
| Distraction Accuracy | Met the acceptance criteria | Distraction Accuracy Testing for 8mm and 11mm nails |
| Usability | Low residual use-related risk, outweighed by benefits | Usability Testing (Human Factors Validation) |
| Bacterial Endotoxin Limits | Met acceptable endotoxin limits | Bacterial Endotoxin Testing per FDA Guidance and ANSI/AAMI ST72 |
| Static Bend Performance | Demonstrated adequate static bending performance during expected clinical use | Static Bend Strength Testing of 8mm and 11mm NOVOS-NAIL in a static three-point bend test |
2. Sample size used for the test set and the data provenance:
- Finite Element Analysis (FEA): The sample size refers to the digital models created. Specific numbers are not provided, but it states "8mm and 11mm NOVOS Limb Lengthening Nails" were analyzed.
- Construct Fatigue Testing: "8mm and 11mm NOVOS-NAIL and the predicate device" were tested.
- Bending Fatigue Evaluation: "8mm and 11mm NOVOS- NAIL" were tested.
- Distraction Accuracy: "8mm and 11mm nail" were tested.
- Usability Testing: The document mentions "A human factors validation was conducted," but does not specify the number of participants.
- Bacterial Endotoxin Testing: Not explicitly stated, but typically involves a batch or representative samples of the sterilized device.
- Static Bend Strength: "8mm and 11mm NOVOS-NAIL" were tested.
The provenance of the data is not explicitly stated in terms of country of origin or whether it was retrospective or prospective. It refers to pre-clinical testing, which is generally conducted in a laboratory setting.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
This information is not provided. The studies outlined are primarily mechanical and usability tests, which typically rely on objective measurements and established standards rather than expert consensus for ground truth establishment. For the usability study, "human factors validation" implies involvement of human factors specialists, but their specific qualifications or number are not detailed.
4. Adjudication method (e.g. 2+1, 3+1, none) for the test set:
No adjudication method is mentioned for any of the described tests. The nature of these pre-clinical tests (mechanical and engineering analyses) usually involves direct measurement against pre-defined specifications rather than subjective assessment requiring adjudication.
5. If a multi-reader multi-case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance:
No MRMC comparative effectiveness study was done. This device is a mechanical implant for limb lengthening and does not involve AI or human "readers" in its primary function, so such a study would not be applicable.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done:
This question is not applicable as the device is a mechanical implant and does not involve an algorithm. The "external actuator" mentioned is a mechanical control, not an AI algorithm.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc):
The ground truth for these pre-clinical tests is established by:
- Engineering Specifications and Standards: For structural strength, fatigue, bending, distraction accuracy, and static bend strength, the ground truth is derived from established mechanical engineering principles, material science, and relevant industry standards (e.g., for fatigue testing, bending strength).
- Regulatory Guidance: For bacterial endotoxin testing, the ground truth is "acceptable endotoxin limits as stated in the FDA Guidance, 'Submission and Review of Sterility Information in Premarket Notification (510(k)) Submissions for Devices Labeled as Sterile,' and 'Pyrogen and Endotoxin Testing: Questions and Answers,' and ANSI/AAMI ST72."
- Human Factors Principles: For usability testing, the ground truth is based on principles of human factors engineering and user experience to identify and mitigate use-related risks.
8. The sample size for the training set:
Not applicable. This document describes pre-clinical testing for a physical medical device, not a machine learning model, so there is no concept of a "training set" in this context.
9. How the ground truth for the training set was established:
Not applicable, as there is no training set for this type of device.
§ 888.3020 Intramedullary fixation rod.
(a)
Identification. An intramedullary fixation rod is a device intended to be implanted that consists of a rod made of alloys such as cobalt-chromium-molybdenum and stainless steel. It is inserted into the medullary (bone marrow) canal of long bones for the fixation of fractures.(b)
Classification. Class II.